Masking tape is widely used by painters and others applying a coating to a surface in order to define a sharp edge on the portion of the surface to be coated. The tape protects a portion of the surface that is not to be coated. Conventional masking tape is longitudinally extended with first and second parallel longitudinal edges and a pressure-sensitive adhesive layer formed on one side of a substrate, or backing, which side we refer to as the bottom side. The adhesive layer permits the masking tape to be removably attached to a surface. The coating may then be applied to the surface so that the first longitudinal edge of the masking tape is also covered by the coating. The tape can then be removed, leaving a straight and well defined edge of the portion of the surface that is coated, corresponding to the position of the first longitudinal edge of the tape.
The pressure-sensitive adhesive is selected so that the tape can easily be removed from the surface. The substrate is typically made from paper and is hand-tearable. The tape is typically manufactured in rolls so that a user can unwind a length of tape and then hand-tear it transversely to remove a strip of tape from the roll.
The paper substrate may be saturated with a latex binder and then dried before the adhesive is applied in order to improve the tensile strength of the substrate to help prevent it from ripping when it is removed. A release coating may also be applied to the top side to facilitate removing tape from a roll.
“Crepe” paper is sometimes used as an effective substrate in masking tape because of its physical properties that make it advantageous over other substrates such as plastic film. The paper is easy to tear by hand while being thick enough and rigid enough to easily position and apply to a surface without flexing or curling.
Such masking tape is typically manufactured in relatively wide sheets that may be cut into narrow widths, such as one inch, and then fed to a rewinder for rolling onto a number of cores to form rolls.
A common problem with paper-based masking tape is that the tape may tear when it is being removed from a coated surface, for example if the coating has been allowed to dry and form a strong membrane. This may happen because of the use of multiple coats, or because of the quality of the coating material. In some cases, the paint membrane may be fractured in a manner that ruins the finished edge. Various methods have been devised to produce tape with enhanced tensile strength to help ameliorate these issues, such as by using plastic film substrates, but these approaches drive up the cost of tape substantially relative to paper-based tape.